The present invention relates to an absorbent article, such as a sanitary napkin, an incontinent pad, a breastfeeding pad, and the like, including a liquid-permeable top layer, a liquid-impermeable back layer, and a liquid-retentive absorbent core disposed between the top layer and the back layer. More particularly, the present invention is directed to an absorbent article which is easy to manufacture, and capable of preventing liquid leakage, irrespective of the quantity of body fluid and motion of the wearer.
In general, absorbent articles such as a sanitary napkin, an incontinent pad, a breastfeeding pad, and the like are known to include a liquid-permeable top layer, a liquid-impermeable back layer, and a liquid-retentive absorbent core disposed between the top layer and the back layer. Such an absorbent article is required to cause body fluid, such as blood, urine, and the like, to rapidly migrate to the absorbent core where it is absorbed and retained with no leakage.
In order to absorb and retain body fluid with no leakage, heretofore, there has been utilized an absorbent article, as disclosed in Japanese Laid-Open Patent Publication No. 4(1992)-152946, Japanese Patent Publication No. 60(1985)-3491, and Japanese Laid-Open Utility Model Publication No. 5(1993)-86321, in which a leakage-preventive wall (or leakage-preventive barrier) is formed on each of the width-wise, left and right side portions, so as to prevent leakage of unabsorbed body fluid deposited on the surface of the top layer.
An absorbent article disclosed in Japanese Laid-Open Patent Publication No. 4(1992)-152946 includes a pair of left and right elastic members expanded in the vicinity of the opposite side portions of a longitudinal, generally central region, inside of a top material and in a longitudinal direction thereof. The individual ends of the elastic members are secured to the top material which is secured to the leakage-preventive material along the elastic members in the vicinity of the longitudinal opposite side portions of the elastic members.
An absorbent article disclosed in Japanese Patent Publication No. 60(1985)-3491 includes a pair of leakage-preventive walls (or barrier walls) formed by wrapping opposite sides of the leakage-preventive material from the back of the absorptive layer with opposite side edges thereof which project from the top surface of the absorptive layer. A liquid-permeable material and the leakage-preventive layer arranged on the top surface of the absorptive layer are fixed by press adhesion to opposite ends or area located at the outside of the opposite ends.
An absorbent article disclosed in Japanese Laid-Open Utility Model Publication No. 5(1993)-86321 includes a pair of leakage-preventive sheets, each disposed at opposite sides of a skin contacting surface along a longitudinal direction thereof. Each leakage-preventive sheet is provided on the distal end portion thereof with a thread rubber for erecting the leakage-preventive sheet. These leakage-preventive walls (or leakage-preventive barriers) are formed by using a top sheet which constitutes the top layer of the absorbent article and a back sheet which constitutes the back layer, or by alternatively using a nonwoven fabric and a film-like material.
However, since such a leakage-preventive wall of the absorbent article either has no liquid absorbing/retentive properties or has only small liquid absorbing/retentive properties, the body fluid tends to leak beyond the leakage-preventive walls when a large quantity of body fluid is deposited on the surface of the top layer, caused by motion of the user, or the like.
Further, as an absorbent article capable of absorbing/retaining a body fluid with no leakage, there has heretofore been known an absorbent article which employs a liquid-shrinkable member which tends to shrink elastically by absorbing a body fluid. Such an absorbent article has such an advantage that it can easily be manufactured in the state that the liquid-shrinkable member has no elasticity.
An absorbent article employing a liquid-shrinkable material is disclosed in Japanese Laid-Open Patent Publication No. 57(1982)-11231, in which a plurality of liquid-shrinkable members are disposed in parallel relation to each other in the longitudinal direction of the absorbent article, generally over an entire central portion at the inside of the absorbent member in a thickness-wise direction. Thus, when a body fluid invades, the absorbent member is subjected to a shirring treatment due to shrinkage of the liquid-shrinkable members. Another absorbent article is disclosed in Japanese Laid-Open Patent Publication No. 57(1982)-35002, in which liquid-shrinkable members are disposed outwardly at each side of the absorbent member in such a way as to cross the longitudinal direction of the absorbent article, so that when the body fluid invades, an external part of each opposing side of the absorbent member stands up due to the shrinkage of the liquid-shrinkable member. A third is disclosed in Japanese Laid-Open Patent Publication No. 6(1994)-121810, in which a three-dimensional gather formation body including liquid-shrinkable members disposed integrally with a gather-forming sheet in the longitudinal and widthwise directions thereof is disposed on a top material, so that when a body fluid invades, the three-dimensional gather formation body stands up from the top material due to shrinkage of the liquid-shrinkable member. In Japanese Laid-Open Publication No. 57(1982)-56502, a liquid-shrinkable member is disposed on an external part of each opposing side of an absorbent member along the absorbent article in a longitudinal direction thereof, so that when a body fluid invades, the absorbent article has a bent shape in the longitudinal direction due to shrinkage of the liquid-shrinkable member.
However, an absorbent article in which the absorbent member is subjected to shrinking treatment has shortcomings that since the liquid-shrinkable member is present generally over the entire central portion at the inside of the absorbing body in the thickness-wise direction thereof and the absorbent article, as a whole, is provided with small irregularities, leakage tends to occur due to the motion of the wearer. With respect to the absorbent article in which the external part of each opposing side of the absorbent member stands up and the absorbent article in which the three-dimensional gather formation body stands up, they have shortcomings in that since both the external part of each opposing side and the three-dimensional gather formation body which stand up, do not have a body fluid absorbing ability, leakage is likely to occur beyond the external part of each opposing side, due to the motion of the wearer. Also, with respect to the absorbent article which is bent in the longitudinal direction, since the liquid-shrinkable member is disposed at an external part of each opposing side of the absorbent body, the absorbent body does not shrink integrally with the liquid-shrinkable member, resulting in unfavorable possibilities wherein the absorbent article is not effectively bent, the fitness is degraded, and among all, the problem of a liquid leakage, which is most likely to occur, at the side edge of the absorbent article is not yet obviated. In addition, since no improvement is seen in the absorptive capacity of a body fluid in any of the above conventional absorbent articles, they cannot appropriately cope with a large quantity of body fluid, thus inevitably resulting in leakage.
It is, therefore, the object of the present invention, to provide an absorbent article which is easy to manufacture, which fits nicely to the wearer""s body, irrespective of the quantity of bodily fluid and motion of the wearer, and which is capable of preventing the possible leakage of body fluid in a reliable manner.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention has achieved the above object by providing an absorbent article comprising a liquid-permeable top layer, a liquid-impermeable back layer, and a liquid-retentive absorbent member, interposed between said top layer and said back layer, wherein said absorbent member is arranged such that a pair of absorbent barrier cuffs having a prescribed width are each formed at the left and right opposing side portions of said top layer in the widthwise direction thereof (this invention is hereinafter referred to as the xe2x80x9cfirst aspect of the inventionxe2x80x9d).
Also, the present invention has achieved the above object by providing an absorbent article comprising a liquid-permeable top layer, a liquid-impermeable back layer, and a liquid-retentive absorbent member, interposed between said top layer and said back layer, wherein said absorbent member is arranged such that a pair of absorbent barrier cuffs having a prescribed width are each formed at the left and right opposing side portions of said top layer in the widthwise direction thereof, and liquid-shrinkable members which can elastically shrink upon absorption of liquid are provided inside the edges of said barrier cuffs and located in the longitudinal direction of said barrier cuffs such that said barrier cuffs are shrunk in the longitudinal direction of said barrier cuffs over a prescribed length (this invention is hereinafter referred to as the xe2x80x9csecond aspect of the inventionxe2x80x9d). Liquid-shrinkable members referred to herein shrink upon absorption of liquid, such as water and body fluid.